tree 1b66e525ffd7a8f23b544a0d8780d82466a65a37
parent 9eaff40b437ec34fd16c8e966b3356a930f52a9e
author Primiano Tucci <primiano@google.com> 1543863806 +0100
committer Primiano Tucci <primiano@google.com> 1543907421 +0000

Add libperfetto_android_internal.so library to access HAL/VNDK

This CL introduces a new shared library, meant to be used
only in in-android-tree builds, to access Android internal
HAL services via hwbinder (and in future maybe other sw
binder interfaces).
The concrete use case is battery tracing (see CLs based
op top of this).
The reasons for splitting off a dedicated .so are twofold:
1) Keep non-NDK dependencies isolated in a standalone target
   and avoid polluting the codebase with #ifdefs.
2) Avoid the memory impact of pulling the various VNDK .so(s)
   unless necessary.

Using hwbinder requires pulling 6 (or more) .so(s), which adds
150 KB of private dirty memory at load time due to linker
relocations.
The plan is to dlopen() libperfetto_android_internal.so
only when required and unload it when unneeded.

Bug: 113076327
Change-Id: I55b76d3c6637fb3604afff6b27870418e4831aa1